Traction device for vehicle wheels



July 8, 1947. c. T. WILLSON TRACTION DEVICE FOR VEHICLE WHEELS Filed Nov. 7, 1945 1571/5158 0r dl fizyie tl gil/s'an y wibbarn 'y Patented July 8, 1947 0 Fri CE 2,423,866 'iTRACTION'DEVIOE FORPVEHIGIJEWHEELS "oh'a'rlesr: Wi11sen,ioanaan;obiin.

Application'Nove'mber 7, rs isg serial Noz 627L219 iiicici'aiins.

..-.=Ai device :fembodyingzthe."inventionfiisel articu- I szla rly adaptedifor use with 10111 as a1 partrof.*ra tire whainnof conventional. form, .':and; it will 7:116 so shownrandidescribed, b'utwitii 1130 be understood that such a device is not sowlimitedasto use and that "it'imay be 'usdwithworras v.azpart of other types:'of-:itractionr devices zadapted for use" 'with vvehiclewheeis having rubber tires.

Conventiona1 tireschains :have. cross: elements consisting: of interconnected emetallie -:links "and "imanyidifferent forms of linksshave'beemproposed and used t'o -zprovide traction for. the tire, parrticulanlyeonz ice. fAitire -chainzsuoh as commonly .znsedihasi azalargeinumberiof points 'or :areas which simultaneously: engage theroad surface'with-the result that the=apressuretis widelyzdistributedand "sisrei2itivelwsniafllat each individualipoint or area :oficontact. .T'Fn-rthenmore, ith-exmetal-lic links wear "rapidlyg'and afterza'z'sh'ort period 'ofuse'any-ini- .iti'ally rounded 1I- oints'-are -worn, or abraded, "-sothat the chainspresents :a relatively large number 'Fofi smooth :flat :faces tort-he icy road 'Fsurface; thus ZStfll further reducinguthe unitipressme at: any 'iODe?pOiI11Z01 aI6Z"bf contact. 7

Iehavei found nthateglasszof suitableg quality conestitute's a: highly "advantageous material/forengaging the road surface to provide traction. :Glass iis partieularly suitable for this purpose" for the: reason-'thatnormal wear or abrasion causes it -to:bec'ome rough and remain rough, .its icegripping:qu*ality -thus being:maintained and even en- =hant'edf as the. result 'of wear. {This is :in contrast vvithliiihe ordinary. metallic elements w of traction E'devices'whi'ch tend to become: smooth asth'e re- Esultebflweargthus decreasing theirflice :gripping quality. One of the objects oftheiinvention:is tohprovide a traction device for thefpurpose .described whereini glassmembers are provided for rcontactingz and engaging an icy road surface to provide-traction.

iAfurther object 0fthe invention is toprovide a traction device ofthe type mentioned wherein the road engaging elements "are hard balls "Droviding very i'shigh itpressures at relatively 'few l pdints. These b'alls are 'preferably'iormed of glass,:but':may:be: formed.- of other materials havf ing approximately I equivalent 'i hardness.

A-still further object of the invention is 1:0 pm- Wide attractionidevice. including hard balls'was -above described,-and so constructed thattheb'alls 'can shift ab'out ithei-r own centers to present .suc- --ce's"sively different portions to the road surface. In ithis 'way the balls'retain their spherical shapes notwithstanding wear.

Other objects of. the invention will i'beuapparent i 'fi'om "the following specification and claims.

"fln th'e drawing: I' have shown in detail-a' pre- "frredembddim'ent ofthe invention;:but'it will:be

niderstood that various changes may beln'nade E -Asshown, it comprises-i two *side: elements 14,

. ist-notrtozberconstrud as defining or limiting -the;'scope aofcithe invention, thexclaims forming a part of this specification being 'relied :uponr-for that; purpose.

5 Dime-drawing,

:Eig 1 1-is=:a:fragmentary.iside viewiof a tire'with 2; tire rchain thereon incorporating the? invention. Figu-Z isia :planvview- Oil-the tire and chain as ishownin-Fig. 1. p t

Fig. 3 is an enlarged face viewrofithat 'portion :of I the :traction "device .to *which :the invention imoreqaarticularly relates.

high-'4 is an edge'ivmw partlyiinisectionsof the epartszshownzin fligghithis'viemalso showingthe cooperative relationshipoofthe: device with the tilteandwwith-the'road surface.

.ifEi'g. '5 is? axdetail view :showing one of the :glass 'b'alls and:illustrating. its 2 condition: after a. short -peniodofqisage. r

r 'Referring to: the: *drawing, "10. representsar vehicle-tire of.---any -usual orrpreferred form and I2 :represents the rim' oni whi'chthet'tirezis mounted.

Carried by the tire I0 is a tirexrchairr which in ilarge; part :is .or'tmay berof conventional :designd.

l and;r'aig plurality' of :cross elements l6, l6.

:Eachrof the: cross elements l-6comprisesia series of; links, :the end' ilihks: of which -are connected with the side 61811161113541, :1 4. Included :in the --ser'i"es 0f links isga'means-for .holding one or'more road engaging members. In'accordanceswith'one phase :of :the inventionathe road. "engaging memsbers are "formed" 'of .iglass and has: concerns the .broader aspects of "the invention the glass :memrber may'bevarioirs'lyshaped.

:rAsshown; each c-r'oss element .has; one. orzmore rhardhalls I8; I 8 whichiaare'. preferably, but snot necessarily, -formed rot ziglass. .If 1. the .balls are formed otherwisewthan 'ofeglas's they should be formedfi'of a material havingza hardness approxi- :m'ating that oiig'la'ss. Three such balls are shown iand this: number isizpre'ferred. For ':holding the ballsrinrpositioniwith respect to a the tire so "that they will be interposed F between the tire and the "road-surf ace asthe twheel'rotates,*arsuitablerhold- :rin'g' meanssor. cage- 20; isjprovide'd which is "connected: in the series of ilinks constituting the :cross .member-JHS. Th amember .or cage 20 "comprises .two' separate platesriL-iz which are, preferably similar in form;butmppositely positioned. These rplates Kare aperturedwtozsa'eceive the severalfbal'ls 1'8 :l 8 :andlflangesml, :24za're rpro idediaround the apertures SOraS itOp9Tfi1y EnC1OSe the balls torre- 'tainrithem. WhenfthlfivbMlSQle 'providedzithey tare preferably so arranged'ithatstheirl centerszare atdahe apexes of a trianglei Such-Jasthat indicated 'byaidotiandsedashlinesz in? Eigab. This arrange- :ment v:p'ro idesJeac'hrjcrnss element Withxazlthree :po'int :contact withzxthe road ;'surface and. dsends f mh h l ti flishbwn,and that the' diaw- 0 to hold the cage 20 in parallelism withithe. road 7 increases.

surface. Preferably, the balls l8, l8 are loosely held by the flanges 24, 24 so that the balls are free to shift about their own centers as the wheel rotates.

It will be observed that Fig. v4 shows the member 20 at its lowermost position with the balls in contact at their tops with the tire I and in contact at their bottoms with a road surface 26 which may be assumed to have a layer of smooth ice thereon. It will be seen that in this position the entire portion of the weight of the vehicle which is carried by the particular wheel is concentrated on the bottoms of the balls which theoretically provide point contacts. Inasmuch as the cage is held in fixed position with respect to the tire, by means of the cross links, the balls cannot roll, and the high pressure contact with the ice provides firm traction.

While I do not limit myself as to any theory or explanation of the effective traction of the balls, it is believed that the high pressure exerted by the balls melts the ice to a limited extent, thus forming shallow recesses in which the balls are entered. These recesses prevent the balls from sliding on the ice.

Inasmuch as the balls are loosely mounted in the cage 20, they are free to shift about their own centers when out of contact with the road surface, so that successively different portions thereof are presented to the road surface at each contact therewith. Inaccordance with standard practice the entire chain is somewhat loose on the tire and gradually shifts circumferentially with respect thereto, thus avoiding excessive wear on the tire at any particular positions. This shifting of the chain tends to facilitate and in fact to causethe shifting or rotation of the balls about their own centers.

A traction device such as that shown is not always used on icy roads and must sometimes be used, frequently for long intervals, on concrete or other roads which tend to cause wear. As is well known, this wear is rapidly destructive of the ordinary chains formed exclusively of metal parts, but I have found that with hard balls, particularly glass balls, wear take place relatively slowly, this being due to a considerable extent to the fact that the balls are constantly shifting, thus preventing Wear at any one place. Furthermore, the wear that takes place with ordinary chains consisting wholly of metallic parts produces numerous small fiat surfaces which are very smooth andwhich are not adapted to grip the ice. Thus, the chains rapidly become less efficient as wear However, with hard balls the wear is not only very slow but is distributed over the entire surfaces thereof, the balls maintaining their spherical shapes Without forming flats.

Furthermore, glass balls, even though initially smooth, become rough with wear and remain rough irrespective of the amount of wear. This is illustrated in Fig. which is intended to show a glass ball after a reasonable amount of use.

Even though the ball may have initially been smooth the surface is roughened as the result of the wear and this roughened surface-serves to very substantially increase the coefficient of friction between the glass ball and the ice.

The balls may eventually be reduced in diameter to such an extent as to no longer serve their intended purpose. They may be removed and replaced by new balls, by opening one of the connecting links so as to permit the plates to be separated sufficiently topermit the substitution of new balls.

What I claim is:

1. A traction device for a vehicle wheel having a rubber tire, the said device comprisin in combination, a member formed of glass, and means for holding the glass member in position with respect to the tire so as to be interposed between the tire and the road surface as the wheel rotates.

2. A traction device for a vehicle wheel having a rubber tire, the said device comprising in combination, a ball having hardness approximating that of glass, and means for holding the ball in positionwith respect to the tire so as to be interposed between the tire and the road surface as the wheel rotates.

3. A traction device for a vehicle wheel having a rubber tire, the said device comprising in combination, a glass ball, and means for holding the ball in position with respect to the tire so as to be interposed between the tire and the road surface as the Wheel rotates.

4. A traction device fora vehicle wheel having a rubber tire, the said device comprising in combination, a ball having hardness approximating that of glass, and a cage for holding the ball in position with respect to the tire so as to be interposed between the tire and the road surface as the wheel rotates, the said cage holding the ball loosely so as to permit it to'shift in position about its own center'when not in engagement with the road surface in order to present successively different portions to the road surface.

5. A traction device for a vehicle wheel having a rubber tire, the said device comprising in combination, a glass ball positioned to be interposed between the tire and the road surface as the wheel rotates, and a cage for loosely engaging the ball so as to hold it in fixed relation to the tire during engagement with the road surface and so as to permit it to shift in position about its own center when not in engagement with the road surface in order to present successively different portions to the road surface.

6. A traction device for a Vehicle wheel having a rubber tire, the said device comprising incombination, a plurality of balls having hardness approximating that of glass positionedto be interposed between the tire and the road surface as the tire rotates, and means for holding the said balls in fixed relation to each other at all times and in fixed relation to the tire during engagement with the road surface.

'7. A traction device for a vehicle wheel having a rubber tire, the said device comprising in combination, a plurality of glass balls positioned to be interposed between the tire and the road surface as the tire rotates,'and means for holding the said balls in fixed relation to each other at all times and in fixed relation to the tire during engagement with the road surface. I

8. A traction device for a vehicle wheel having a rubber tire, the said device comprisin in combination, a plurality of balls having hardness approximating that of glass, and means for holding the balls in fixed relation with each other with their centers at apexes ofv a triangle and for holdin them in such positions with respect to the-tire that they are inter- I posed between the tire and the road the tire rotates.

9. A traction device for a vehicle wheel having surface as a rubber tire, the. said device comprising in combination, a plurality of balls having hardness approximating that of glass, and a cage for holding the balls in fixed relation with each other for holding them in such positions with respect to the tire that they are interposed between the tire and the road surface as the tire rotates, the said cage holding the balls loosely so as to permit them to shift in positions about their own centers when not in engagement with the road surface in order to present successively difierent portions to the road surface.

10. A traction device for a vehicle wheel having a rubber tire, the said device comprising in combination, a plurality of glass balls, and a cage for holding the balls in fixed relation with each other with their centers at apexes of a triangle and for holding them in such positions with respect to the tire that they are interposed between the tire and the road surface as the tire rotates, the said cage holding the glass balls loosely so as to permit them to shift in positions about their own centers when not in engagement with the road surface in order to present successively different portions to the road surface.

11. A traction device for a vehicle wheel having a rubber tire, the said device comprising in combination, a. plurality of hard balls positioned to be to interposed between the tire and the road surface as the tire rotates, and a cage comprising two apertured plates for holding the said balls in fixed relation to each other at all times and in fixed relation to the tire during engagement with the road surface.

12. A tire chain comprising circumferential side elements and a plurality of cross elements connecting the side elements, each of the cross elements including a ball having hardness approximately that of glass and means for holding the ball in position with respect to the tire so as to be interposed between the tire and the road surface as the tire rotates.

13. A tire chain comprising circumferential side elements and a plurality of cross elements connecting the side elements, each of the cross elements including a ball having hardness approximately that of glass and a cage for holding the ball in position with respect to the tire so as to be interposed between the tire and the road surface as the tire rotates, the said cage holding the ball loosely so as to permit it to shift in position about its own center when not in engagement with the road surface in order to present successively different portions to the road surface.

14. A tire chain comprising circumferential side elements and a plurality of cross elements connecting the side elements, each of the cross elements including a glass ball and a cage for holding the glass ball in position with respect to the tire so as to be interposed between the tire and the road surface as the tire rotates, the said cage holding the glass ball loosely so as to permit it to shift in position about its own center when not in engagement with the road surface in order to present successively different portions to the road surface.

15. A tire chain comprising circumferential side elements and a plurality of cross elements connecting the side elements, each of the cross elements including a plurality of balls having hardness approximating that of glass and a cage for holding the balls in fixed relation to each other and in such positions with respect to the tire as to be interposed between the tire and the road surface as the tire rotates, the said cage holding the balls loosely so as to permit them to shift in positions about their own centers when not in engagement with the road surface in order to present successively different portions to the road surface.

16. A tire chain comprising circumferential side elements and a plurality of cross elements connecting the side elements, each of the cross elements including a plurality of balls having hardness approximating that of glass and a cage for holding the balls in fixed relation to each other with their centers at the apexes of a triangle and for holding the balls in such positions with respect to the tire as to be interposed between the tire and the road surface as the tire rotates, the said cage holding the balls loosely so as to permit them to shift in positions about their own centers when not in engagement with the road surface in order to present successively different portions to the road surface.

CHARLES T. WILLSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,810,191 Stueckle June 16, 1931 FOREIGN PATENTS Number Country Date 18,217 Australia Feb. 4, 1929 

